title: Interferometric null test of a deep parabolic reflector generating a Hertzian dipole field.
abstract: We report on interferometric characterization of a deep parabolic mirror with a depth of more than five times its focal length. The interferometer is of Fizeau type; its core consists of the mirror itself, a spherical null element, and a reference flat. Because of the extreme solid angle produced by the paraboloid, the alignment of the setup appears to be very critical and needs auxiliary systems for control. Aberrations caused by misalignments are removed via fitting of suitable functionals provided by means of ray tracing simulations. It turns out that the usual misalignment approximations fail under these extreme conditions.
authors.affiliation: Friedrich Alexander University of Erlangen-Nürnberg, Staudtstr. 7/B2, 91058 Erlangen, Germany.
authors.forename: Gerd
authors.initials: G
authors.lastname: Leuchs
authors.forename: Klaus
authors.initials: K
authors.lastname: Mantel
authors.forename: Andreas
authors.initials: A
authors.lastname: Berger
authors.forename: Hildegard
authors.initials: H
authors.lastname: Konermann
authors.forename: Markus
authors.initials: M
authors.lastname: Sondermann
authors.forename: Ulf
authors.initials: U
authors.lastname: Peschel
authors.forename: Norbert
authors.initials: N
authors.lastname: Lindlein
authors.forename: Johannes
authors.initials: J
authors.lastname: Schwider